1. Field of the Invention
This invention relates to a method and apparatus for efficiently developing a photosensitive material which has been exposed to the light for printing.
2. Description of the Prior Art
Ordinarily, on a photograph printing apparatus, a photosensitive material is fed continuously from a roll to an exposure table provided in the exposure unit where an image on the negative film is printed on each frame by exposing it to the light. Next, the photosensitive material is fed to a developing unit by a carrier unit. It is developed while passing through a tank containing different developing solutions. The photosensitive material is then dried and the photographs are delivered.
The photosensitive material to be exposed to the light on the exposure table is previously cut into sheets of paper for the convenience of developing. The sheets are fed in line to the developing unit in which a space of several tens of millimeters is provided to avoid contact between each pair of sheets of the photosensitive material.
In such conventional film printing apparatus, the developing speed for developing the photosensitive material was usually much lower than the speed for printing the photosensitive material by exposing it to the light. Thus, in order to improve the treatment capacity of the film printing apparatus, it was necessary to improve the treatment capacity of the developing unit.
However, in such a conventional method, although the treatment speed for each frame was set as high as possible, there was a limit. In order to overcome this problem, it has been proposed to increase the rack length of the carrier unit for carrying the photosensitive material in the developing unit to increase the number of the sheets developed per hour, and thus increase the treatment speed in the developing unit.
With increase in the rack length, the entire size of the developing unit as well as the size of the tank increased, too. Thus, the amount of developing solutions, both main and supplemental solutions, inevitably increased. For example, in the photosensitive material having a certain width, to increase the treatment capacity from 500 sheets per hour to 1000 sheets per hour, the rack length had to be 210% longer and the amount of the main and supplemental developing solutions had to be increased to 200%.